Lignin peroxidase isoenzymes

Physico-chemical properties of Lignin peroxidase isoenzymes from Phanerochaete... 

Farrell RL, Murtagh KE, Tien M et al (1989) Physical and enzymatic properties of lignin peroxidase isoenzymes from Phanerochaete chrysosporium. Enzyme Microb Technol 11 322-328... 

Fig. 5 Separation of lignin peroxidase isoenzymes using the 8 ml radial methacrylate monolithic columns. Stationary phase CIM DEAE 8 ml column. Conditions buffer A 10 mM acetic buffer, pH 6.0 buffer B 1 iVf acetic buffer, pH 6.0 flow rate 8 ml/min gradient 10-70% buffer B in 2.25 min sample supernatant from Phanerochaete chrysosporium cultivation injection volume 500 p.1 detection UV at 409 nm.

Purification. One main peak was observed with detection at 405 nm, when purified lignin peroxidase was analyzed by Mono Q chromatography. The retention time of the main peak was 11.8 min and its area was 98.9% of the total peak area. Possibly the enzyme solution contains, however, two isoenzymes which have very similar properties. The Kj of the purified lignin peroxidase for veratryl alcohol was 139 on the basis of Eadie-Hofstee plot. 

Generation of CIII from GS occurs when the enzyme acts as an oxidase in the presence of superoxide ion. This reaction has been observed in horseradish peroxidase isoenzymes C and A2 [28, 53, 63], lignin peroxidase [46], myeloperoxidase [69], and bovine liver catalase [64], The rate constant for the reaction of GS with superoxide increases with a decrease of pH suggesting that the reacting species is HO2 instead of C - [64], The physiological relevance of the hydroxyperoxyl radical has been recently reassessed [70],... 

S Lobos, J Larram, L Salas, D Cullen, R Vicuna. Isoenzymes of manganese-dependent peroxidase and laccase produced by the lignin-degrading basidiomycete Ceriporiopsis subvermispora. Microbiology-UK 140 2691-2698, 1994. 

Another technique that will be of increasing help in our understanding of extractives biosynthesis are detailed studies of the location of various enzymes within the tree. A recent example of such work is that of Stich and Ebermann (55) who showed that isoenzymes of peroxidase and polyphenol oxidase were identical in the sapwood and heartwood of oak. This work shows that there is a potential for polymerization of monomers to lignin in unlignified parenchyma cells at the sapwood/heartwood boundary as well as in the zone of active lignification close to the cambium. It could also help to explain the formation of the heartwood lignin-like polymers mentioned in Section 11.6.5. 

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